Watch An Early Clip Of Tonight’s New PBS Documentary About NSA, ‘US Of Secrets’

The first part of PBS’s new Frontline documentary chronicling the rise of the U.S. surveillance state in the wake of 9/11 aired last week to broad critical acclaim, and was described as “simply best and most important work of non-fiction television this year” by the Baltimore Sun.

Another producer said the in-depth examination of National Security Agency bulk surveillance — including that of Americans — “makes House of Cards look like Blue’s Clues.” Part two, which airs tonight on PBS and online, promises equally deep and gritty coverage of the most expansive communications dragnet ever conceived by government, and the size-equivalent intelligence leaks that continue to follow as a result.

Tuesday’s latter part covers NSA’s relationship, history and hijacking of Silicon Valley tech giants like Google, Apple and Microsoft — including the first major headline-grabbing revelation from former contractor and NSA leaker Edward Snowden.

The PRISM Internet surveillance program collected emails and other vast, varied forms of metadata on users within and outside of the U.S., and the early clip released below explores how the signals intelligence agency compromised Google tracking technology meant for online targeted advertising, and used it to surveil targets.

“The moment you allow people to look at the content of your communication for some advertising purpose is the moment that the government is gonna come along and say, ‘If you’re gonna let them listen in for advertising, why don’t you let us listen in for anti-terrorism or for serious crimes?'” University of California Berkeley lecturer and privacy expert Chris Hoofnagle says in the documentary.

“And it becomes very difficult for courts to say that the private sector can listen in but the government can’t.”